Nulllable warnings do not show as errors with WarningsAsErrors

[MatisseHack]

I am trying to use <WarningsAsErrors>nullable</WarningsAsErrors> in a project, but nullable warnings are still not showing as errors. This is a simple project file that exhibits the issue:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <WarningsAsErrors>nullable</WarningsAsErrors>
  </PropertyGroup>
</Project>

The warnings are properly treated as errors when running dotnet build, but don't work in the editor. These symptoms seem similar to dotnet/roslyn#38371

[furai]

Did this stop working in recent versions or do I need some extra config to make it work? It's not working for me currently.

EDIT: It seems there is some discrepancy with how msbuild vs omnisharp treats those. In msbuild it's enough to set <WarningsAsErrors>Nullable</WarningsAsErrors> and for ominsharp I still have to add individual CSxxxx to make it work which is less than ideal.

[furai]

Could we reopen this issue? Or should I create a new one? @JoeRobich

[JoeRobich]

@furai Please create a new one.